Air heater



April 25, 1967 K. S.JENSON ETAL 3,315,657

AIR HEATER Filed Dec. 51, 1963 3 Shee ts-Sheet 1 Aprifl 25, 1967 K. S. JENSON ET AIR HEATER 3 Sheets-Sheet 2 Filed Dec. 31, 1963 Apr-i2 25, 1967 K, JENSO'N ET AL 3,315,657

AIR HEATER 5 Sheets-Sheet 5 Filed Dec. 31, 1963 United States Patent 3,315,657 AIR HEATER Kenneth S. Jenson and Frederick W. Suhr, Wisconsin Rapids, Wis, assignors to Preway, Inc., a corporation of Wisconsin Original application Dec. 31, 1963, Ser. No. 334,693, new Patent N0. 3,274,989, dated Sept. 27, 1966. Divided and this application Mar. 1, 1966, Ser. No. 530,849 2 Claims. (Cl. 126-116) This invention relates to air heaters and is a division of our copending application Ser. No. 334,693, filed Dec. 31, 1963, now Patent No. 3,274,989, granted Sept. 27, 1966.

Air heaters of the type installed and used within living areas of dwellings have in recent years come more and more into use. Such heaters include space heaters as well as heaters for heating the entire dwelling. Such an air heater is conveniently installed with an exhaust and/ or intake conduit through a wall or ceiling structure. Hazards may be created by leakage of vent ducts. Where the burner is used for heating purposes, the efiiciency of the heater may be decreased by flow of exhaust gases back into the burner intake. Another hazard is created by foreign objects or birds entering the exhaust conduits. Also, wind blowing directly at the exhaust conduit creates a reverse flow of combustion gases.

It is therefore the principal object of this invention to overcome or alleviate problems such as those discussed above.

It is another object of this invention to provide an air heater of the character described including an exhaust conduit comprised of a plurality of concentric tubular members which prevent leakage.

It is a further object of this invention to provide such an exhaust conduit which includes an inner cylindrical conduit suspended centrally of the innermost tubular member to prevent foreign objects or birds from entering the exhaust conduit.

It is still another object of this invention to provide an exhaust conduit of the character described which has deflector means to prevent the reverse flow of combustion air when the wind is blowing.

Another object of this invention is to provide a new and useful vent arrangement for use with such air heaters.

Other objects and advantages will become apparent from the following detailed description taken in connecnection with the accompanying drawings in which:

FIGURE 1 is a perspective view of a form of air heater of this invention;

FIGURE 2 is a view looking into the air heater of FIGURE 1 with the front door removed;

FIGURE 3 is a section through the air heater of FIG- URE 1 along lines 33 of FIGURE 2, with the air heater mounted on and supported by a wall of a building; and

FIGURE 4 is a view of a portion of the rear of the air heater of FIGURE 1 showing a form of venting arrangement.

In general the embodiment of air heater illustrated in the drawings is of the type in which air is drawn in from a room or building to be heated and the air is passed in heat exchange with a combustion chamber wherein fuel is being burned. The heated air is then discharged back to the room or building and air is continuously passed through the heater while on, for heating purposes. The air for supplying the burner is drawn in through a separate intake system from outside of the room or building and the combustion gases and fumes are exhausted exteriorly of the room or building.

Referring to the drawings, as seen generally in FIG- URE 1, the embodiment illustrated includes a hexahedral casing having outer walls on each of the six sides thereof.

3,315,657 Patented Apr. 25, 1967 As seen in FIGURES 1-3, the outer side walls 12 and 13 and top wall 14 are formed of a single sheet member 15 and have inwardly turned flanges 16 overlapping and abutting peripheral edges of an outer sheet member 19 of a rear wall 20. The front edge of sheet 15 is folded inwardly within the casing at 21 and thence downwardly in an inward flange 22 providing a recess flange or angle member 23, the purpose for which will be seen hereinbelow. Flange 22 forms one leg of the angle member 23, the other leg terminating at fold 21. The rear wall 20 includes sheet member 19 and an internal sheet support member 24 facially secured thereto and terminating at its upper end in a channel-like configuration at 25 for adding rigidity to the upper rear edge of the casing.

The bottom wall 26 of the casing includes a bottom sheet 29 abutting inwardly turned flanges 30 of sheet member 15. Sheet 29 is backed with an inner sheet 31 and secured thereto, sheet 31 having a rearward channellike portion 32 which is secured by one channel leg to sheet 24. A rear flange 33 of sheet 29 turns upward overlying sheet 19 of rear wall 20, sheet 19 being backed by brace or sheet member 24 which is secured to both flange 33 and sheet 19. Inner sheet 31 is secured to the upper faces of flanges 30 and backs the abutting joint between flanges 30 and sheet 29.

The front edge of sheet 29 also terminates in a recessed angle portion 23, the bend at 21 clamping and holding the front edge of sheet 31 between the opposing surfaces of sheet 29 in forming the angle 23.

A second casing wall structure is provided generally enclosing a combustion and air heating portion 34 of the illustrated air heater, except for the air intake and outlet passages thereof. The second casing wall structure is spaced inwardly from the outer casing structure to define a flow path 35 between the inner and outer casing structures in communication with an air intake chamber 36 for delivery of air to the heater from the room to be heated by the heater. The flow path 35 insulates outer casing top wall 14, rear wall 22, bottom wall 29, and side wall 12 from the combustion and air heating portion 34 of the device so that these walls remain cooler than otherwise. End 13 and the front of the illustrated air heater include air inlets and outlets, respectively, for circulating air through the heater and are not provided with the insulating air flow path, i.e. not backed by the inwardly spaced inner casing.

The inner casing, indicated generally at 39 is composed of a plurality of sheet members secured together by overlapping flanged edges to form an enclosure spaced inwardly from walls 12, 14, 20 and 29 suflicient to define the air flow passage 35 between these walls and casing 39. Casing 39 includes out-turned flanges 40 which are secured to legs 22 of angles 23 by machine screws 41, or the like. Casing 39 is also welded to channel member 25 and may rest on or be welded to channel member 32. Channel members 25 and 32 extend the length of the rear wall 19, blocking air communication between the portion of passage 35 along wall 19 and the portion of passage 35 along top wall 14 and bottom wall 29.

Casing 39, it will be noted, is open at the end disposed toward end -13 of the outer casing of the device. A sheet metal member 42 is configurated to define an air chamber 44 and has down-turned or inwardly turned flanges 43 along the front and rear edges thereof. Rear flanges 43 are secured to the interior surface of the rear wall of casing 39. Air chamber 44 is the intake chamber for receiving air to be used by a burner 45 mounted by suitable means within chamber 44. Burner 45 is illustrated in the form of an automatic gun-type power burner, a type of burner used in central heating plants. Such a burner is electrically controlled for ignition and shut-oft and is capable of drawing surrounding air and creating suflicient power draft for burning of the fuel, in this case, oil. The oil is introduced to the burner in normal manner by feed lines (not shown), flame and combustion gases being discharged from burner 45 through outlet passage 46 into a pot portion 49 of a furnace 50 defining a combustion chamber internally thereof. Furnace 50 is provided with a service port cover 51 bolted in place as at 52. The combustion gases from combustion chamber 50 are passed through an outlet duct or passage 53 terminating in tubular projection 54 for exhausting such combustion gases from the device. Force for draft at the burner and for exhausting the gases is provided integrally in the burner structure.

Upstanding from sheet 42 is a sheet member 55 extending the depth of the air heater casing, and, with sheet 42 and casing 39 defining air intake chamber 36 to the left thereof, as viewed in FIGURE 2, as a chamber separate from the air heating chamber 34. The sheet 55 is secured along its top edge to flange 56 projecting downward from the portion of casing 39 spaced inwardly from wall 14.

The lower edge of sheet 55 is secured by flange 59 to sheet 42 and the rear edge is secured to the rear wall of casing 39. An opening 60 is provided through sheet 55 surrounded by a skirt 61 defining a throat opening 61 extending inwardly into chamber 34. Mounted within the throat member 61, coaxial therewith, is a blower or fan having a plurality of blade members 62 driven by a motor 63 suitably mounted in chamber 36 by brackets (not shown).

The front wall of the illustrated air heater device is shown generally by reference numeral 64. Vertical and horizontal brace members 65, each having a cross-sectional T-shape, are interconnected across the front of the casing and are secured at their ends to each other or to angle legs 22, providing continuation of the recessed flange or leg 22 vertically spanning the front and horizontally spanning a portion of the front, forming a frame structure of front wall 64. A door 69 is mounted by hinges 70 to the rearward folded portion of wall 13 adjacent fold 21. Door 69 is provided with a handle 71 and is openable and closable on hinges 76. Door 69 is provided with a snap-catch (not shown) of conventional design for securing the door in closed position, but releasable for opening the door. The inner surface of door 69, when door 69 is closed, is flush against and abuts angle 43 and the forward edge of plate -5 to generally seal chamber 36 from chamber 34 except via port 60. The inner surface of door 69 also seals off and forms the front wall of combustion air chamber 44, preventing use of appreciable amounts of room air for combustion purposes. Door 69 may conveniently be double-walled and may include insulation between the two walls, if desired. Door 69 is provided for gaining access to the burner 45, blower 63 and the electric system for controlling the blower and burner, for repair thereof, and for the replacement of filter elements as will be described hereinbelow.

The electrical system for control of the burner is illustrated as mostly mounted within box 68; the system includes the usual connections for controlling the burner and blower by a thermostat removed from the heater, e.g. mounted on a wall of the room. Box or electrical system 68 is mounted on wall 42a in chamber 44 and is thereby isolated from the hotter chamber 34; also, sheet member 42, of which wall 42a is a portion blocks substantial heat exchange between the outlet chamber 53 from furnace 50 and the electrical system. With door 69 closed the peripheral edges thereof are facially disposed'against flanges 22 and an arm of T-frame member 65. Thus, door 69 is used to close and substantially seal a plurality of chambers from each other without employing permanent seals of compositions which may deteriorate with use. Front wall 64 also includes a pair of grill panels illustrated as being of generally square configuration and shown generally by reference numeral 72. Each grill panel includes a frame 73 supporting a plurality of parallel vanes 74 having a distinct curvature for directing air passing therebetween laterally of the vanes, vanes 74 being secured against movement in the illustrated form. Handles 75 are provided on each of grill panels 72. A tension spring 76 is provided for each panel 72, anchored at one end to a generally centrally disposed portion of panel 72 and anchored at the other end to the interior surface of casing 39 spaced inwardly from wall 12. Tension spring 76 biases grill member 72 inward against a framework defined by flanges 22 and an arm of T-braces 65. Either or both of the grill members 72 may be grasped by handles 75, pulled outward and reorientated 90 in rotation or in multiples of 90 in rotation and reinserted, spring 76 being sufficiently resilient to permit withdrawal of the panels 72 for reorientation thereof and having sufficient strength to retain panel 72 in the position shown in FIGURE 1 after reorientation. Thus, by reorientating panels 72 as desired, warm air passing from chamber 34 outwardly through vanes 74 may be directed upward, downward, or to either side or in any combination of two such directions.

Opening of door 69 and removal of grills 72 gives access to the complete interior of the device for servicing of component in any of the chambers thereof. The rear wall of casing 39 is provided with a plurality of ports 79 for communicating the air space 35 between casing 39 and rear wall 20 with chamber 36. The portion of space along rear wall 20 is in air communication with the portion of air space 35 along end wall L12, but is blocked by channel members 25 and 32 from communication with the portions of air space 35 along top wall 14 and bottom wall 29. The left edge, as viewed in FIG- URE 2, of the rear wall of casing 39 abuts and is secured to side wall I13 adjacent an edge thereof peripherally of the louvers 77 in wall 13. The top and bottom walls of casing 39 stop short of wall 13 at the left in FIG- URE 2. Thus, the ends of the portions of air chamber 35 lying beneath top and bottom walls \14 and 29 are open for receiving air, as at reference numeral 80, from the slot ports defined in wall 13 by louvers 77. It will be seen that .a pressure drop at ports 79, e.g. created by blower 62, would tend to draw air through open ends 80, along walls 14 and 29, thence into the portion of air space 35 beneath wall 12, into the portion of air space 35 beneath rear wall 20 and through ports 79 into chamber 36. A flowing blanket of air beneath walls 12, 14, 20 and 29 is thereby created. This flowing blanket of air insulates the walls from the combustion and air heating chamber portion 34 of the device providing external surfaces of the thusly insulated walls which are cool to the touch.

However, the total supply of air to chamber 36 is not obtained from the insulating blanket of flowing air. Substantial amounts of air are also drawn in through end wall 13. Accordingly, louvers 77 provide a plurality of flow slots through wall 77. Wall 13 is backed by filters 78 so that air passing between louvers 77 passes through filters 78 into chamber 36, filters 78 being held in place by peripheral flanges projecting inwardly from the top, rear and bottom walls of casing 39 and forming a frame 8 1, the filters being contained between flanges 81. The filters 78, however, do not extend across openings 80 of air space 35. For removal of the filters, door 69 is opened and filters 78 may he slid out from the front of the casing for cleaning, replacing or the like. Reinsertion of the filters will be apparent. Door 69, when closed, seals against the front edge of filters 78.

The filters 78 are packed filters having fibers sufliciently compacted to create resistance to flow into chamber 36 therethrough. With blower 62 drawing air from chamber 36, filters 78 serve to provide a pressure drop across the filters. As a result, air is readily drawn into and through air space 35 and into chamber 36, maintaining the blanket of air beneath the outer wall of the air heater device. Air is also drawn into chamber 36 through filters 78 and the resistance to flow, or pressure drop, created by filters 78 is suflicient to provide the desired or proper amount of cooling air flowing through chamber 35 for the desired cooling effect on the heater outer walls.

Outlet duct 54 projects through and is secured to the rear wall of casing :39 by means of a circular angle member 82 secured to the outer surface of duct 54 and the inner surface of casing 39. A plurality of concentric tubes 83, 84 and 85 is provided with tube 83 slidably fitted over tubular duct 54. Tube 83 is the central tube of the plurality. A brace 86 is hooked at one end around the outer end of tube 85 and can be mounted at its other end to suitable building structure for supporting the outlet end of the assembly of concentric tubes. A flue shield liner is mounted within tube 85 by suitable spacer mounting brackets. Tube 84 projects through the liner. Two concentric flanges '89 and 90, each concentric with duct 54, are secured to the outer surface of the rear wall of casing 39 and project outwardly through rear wall 19, as does duct 54. Tubes 84 and 85 are slidably received over flanges 89 and 90 respectively forming a telescoped assembly between tubes 83 through 85 secured to duct 54 and flanges 89 and 90 by force fit.

Cross braces 92 and 93, illustrated as long bolts, impale each of tubes 83 through 85 generally along diameters thereof, bolts 92 and 93 being illustrated as disposed along ditferent angular dispositions with respect to each other, e.g. at right angles to each other.

Bolts 92 and 93 also impale an inner tube member 94, suspending tube 94 generally cent-rally within tube 83.

Bolts 92 and 93 receive nuts at their straight ends and serve to maintain general concentric disposition of tubes 8-3 through 85 which are also supported concentrically by exhaust duct 54 and flanges 89 and 90. Attached to and extending part way across the end of tubes 83 there is provided a deflector member in the form of a rigid flap 95, the function of which will be more evident hereinbelow. Deflector 95 is secured to the upper surface of the outer end of tube 83 by a flange portion welded to tube 83.

A chain 96 extends through small aligned holes in the lower wall portions of each of tubes 94 and 83 through 85. Chain 96 is held generally taut and secured at opposite spaced ends by cotter keys 97 which retain the chain in position by functioning as stops against the inner surface of tube 94 and the outer surface of tube 85. Chain 96 aids in holding the tubes 94 and 83 through 85 in concentric disposition and prevents incorrect placement of the tubes during installation.

As gases are exhausted through duct 54 there may be some leakage between duct 54 and the tube 8-3 telescoped thereover, the connection therebetween being a forced fit or sliding connection. For this reason, concentric tube 84 is provided surrounding tube 83 to conduct gases which may leak through the connection outwardly away from the area adjacent wall 20 and casing 39 where such gases may be carried into the air intake system and eventually be discharged into the room or building being heated. For like purpose, concentric tube 85 is provided surrounding tube 84 to direct any gases which may leak between flange 8'9 and tube 84 outwardly away from wall 20.

Disposed below the combustion gas exhaust system described above is the combustion air inlet system which includes a tubular member 98 telescoped and force fitted over a flange 99. The flange 99 defines the inlet duct for air being drawn into chamber 44 for use by burner 45. Cross brace members .100 and 101, in the form of bolts and nuts, suspend inner tube member 102 generally concentrically within tube 98.

Cross brace members 92, 93, 100 and :-1, in addition to functioning for bracing purposes also help to block passage of objects inwardly through ducts 54 and 99 during operation of the device or otherwise. The centrally mounted tubes 94 and 102 are also provided for preventing birds from entering and building nests.

The purpose of the deflector is to prevent reverse flow of combustion gases when the wind is blowing directly at the discharge end of tube 83. With wind blowing directly against the open ends of tubes 83 and 98, deflector 95 creates a cross flow of air which increases or aids the discharge of combustion gases from tube 83 because the wind can enter inlet tube 98 easier than outlet tube 83.

The heater device may be conveniently installed by setting the device on a supporting surface at the desired location and connecting the burner and electrical system in the usual manner to fuel line and thermostat. Means illustrated at 105 (FIGURE 3) are also provided for mounting the device in a position suspended from a wall, desirable where floor space is limited. Accordingly, each mounting 105 includes a circular hole 106 in rear wall 20 of sufficient size to clear the head of a bolt 107 or screw or the like. A slot 108, at least as wide as the shank of bolt 107 and narrower than the head of bolt 107, extends upwardly from hole 106. A plurality of such mountings is provided, each at a different location in rear wall 20, preferably near the top of wall 20. In installing, bolts 107 are secured into the wall at positions spaced in accordance with the spacings of holes 105, with the heads of bolts 107 protruding slightly. The heater is lifted to the wall and holes 105 are guided over the bolt heads and the bolt shanks are directed into slots 106. Burner and electrical connections, etc. are then made to the mounted device.

In operation of the device, motor 63 and burner 45 are started in the usual manner and air is drawn by burner 45 through intake duct 99 into combustion air chamber 44, thence through burner 45 and the resulting flame and combustion gases are ejected into combustion chamber 50 and are exhausted through ducts 53 and 54 and 83 exteriorly of the room or building. Passage of air through chamber 44 serves to keep electrical system 68 cool. Meanwhile, fan 6-2 draws air from chamber 36 and forces the air through chamber 34 in heat exchange with furnace or combustion chamber 50 and thence outward through grill members 72 for direction of air into the room as desired. The air is heated in chamber 34. Fan 62 draws air into chamber 36 through louvers 77 and thence in separate paths to chamber 36, one path through filter 78 and the other path through the air space 35 beneath the surfaces of walls .12, 14, 20 and 29. Thus, there is provided a separate flow system, including two flow paths, for drawing air from a room and heating and returning the air and a separate fiow system for drawing air from exteriorly of the room for burning fuel by the burner for heating the air by heat exchange with the first flow path, the combustion gases being exhausted exteriorly from the room or building. The air entering chamber 36 via fiow path 35, is, in effect, predominately passed in heat exchange with chamber 34 for preheating the air prior to its entry into chamber 34, thereby improving the efliciency of the heating operation while maintaining cooler exterior casing walls.

We claim:

1. A gas conduit for passage of gases relative to an air heater comprising, a plurality of tubular conduit members of different diameters positioned one within the other in spaced-apart relation, and means for holding said conduit members in spaced-apart relation including a pair of rods at approximately right angles to each other and each extending diametrically of and loosely through openings in the walls of the tubular members, the rods being of a length to have the rod ends extending beyond the outer perimeter of the outermost tubular member whereby the angular relation of the rods holds the tubular members in associated relation and the rods can be manipulated externally of the conduit, and means on the rods engage- 7v able with the outermost tubular member for holding the rods in position.

2. An air heater comprising a housing; an air heating chamber within said housing adapted for passing air therethrough; a furnace system defined by a walled conduit extending through said air heating chamber in heat exchange therewith, said furnace system including a combustion chamber having wall means in heat exchange with the air heating chamber, burner means for burning fuel in said combustion chamber in the presence of air, air intake means for drawing air into said burner means, outlet means for discharging combustion gases from said combustion chamber, separate conduit means communicating with said air intake and outlet means, projecting through a wall of said housing and adapted for installation through a wall structure for-communication with air on the other side of such wall structure, each of said conduit means comprising, a plurality of tubular conduit members of different diameters positioned one Within the other in spaced-apart relation, and means for holding said conduit members in spaced-apart relation including a pair of rods at approximately right angles to each other and each extending diametrically of and loosely through openings in the walls of the tubular members, the rods being of a length to have the rod ends extending beyond the outer perimeter of the outermost tubular member whereby the angular relation of the rods holds the tubular members in associated relation and the rods can be manipulated externally of the conduit, and means on the rods engageable with the outermost tubular member for holding the rods in position.

References Cited by the Examiner UNITED STATES PATENTS 1,615,909 2/1927 Nance 126307 2,117,511 5/1938 Scott.

2,319,131 5/ 1-943 Harrington 126-312 2,632,435 3/ 1953 Lundstrum 126-90 2,998,764 9/1961 Bedell et a1 12685 3,028,843 4/1962 Carlson et al.

3,087,408 4/1963 Carr 98-46 JAMES W. WESTHAVER, Primary Examiner. 

2. AN AIR HEATER COMPRISING A HOUSING; AN AIR HEATING CHAMBER WITHIN SAID HOUSING ADAPTED FOR PASSING AIR THERETHROUGH; A FURNACE SYSTEM DEFINED BY A WALLED CONDUIT EXTENDING THROUGH SAID AIR HEATING CHAMBER IN HEAT EXCHANGE THEREWITH, SAID FURNACE SYSTEM INCLUDING A COMBUSTION CHAMBER HAVING WALL MEANS IN HEAT EXCHANGE WITH THE AIR HEATING CHAMBER, BURNER MEANS FOR BURNING FUEL IN SAID COMBUSTION CHAMBER IN THE PRESENCE OF AIR, AIR INTAKE MEANS FOR DRAWING AIR INTO SAID BURNER MEANS, OUTLET MEANS FOR DISCHARGING COMBUSTION GASES FROM SAID COMBUSTION CHAMBER, SEPARATE CONDUIT MEANS COMMUNICATING WITH SAID AIR INTAKE AND OUTLET MEANS, PROJECTING THROUGH A WALL OF SAID HOUSING AND ADAPTED FOR INSTALLATION THROUGH A WALL STRUCTURE FOR COMMUNICATING WITH AIR ON THE OTHER SIDE OF SUCH WALL STRUCTURE, EACH OF SAID CONDUIT MEANS COMPRISING, A PLURALITY OF TUBULAR CONDUIT MEMBERS OF DIFFERENT DIAMETERS POSITIONED ONE WITHIN THE OTHER IN SPACED-APART RELATION, AND MEANS FOR HOLDING SAID CONDUIT MEMBERS IN SPACED-APART RELATION INCLUDING A PAIR OF RODS AT APPROXIMATELY RIGHT ANGLES TO EACH OTHER AND EACH EXTENDING DIAMETRICALLY OF AND LOOSELY THROUGH OPENINGS IN THE WALLS OF THE TUBULAR MEMBERS, THE RODS BEING OF A LENGTH TO HAVE THE ROD ENDS EXTENDING BEYOND THE OUTER PERIMETER OF THE OUTERMOST TUBULAR MEMBER WHEREBY THE ANGULAR RELATION OF THE RODS HOLDS THE TUBULAR MEMBERS IN ASSOCIATED RELATION AND THE RODS CAN BE MANIPULATED EXTERNALLY OF THE CONDUIT, AND MEANS ON THE RODS ENGAGEABLE WITH THE OUTERMOST TUBULAR MEMBER FOR HOLDING THE RODS IN POSITION. 